Electromagnetic switch



UNITED STATES P TEN OFFICE.

SAMUEL n. norms, or wILKINsB'Une, rEnnsY vAnIe, assrenon 'rowns'rlnenoose ELECTRIC a m MANUFACTURING coMrnNY, A conronarron or PENN- SYLVANIA.

Application filed. May 20,

T all whom. it may concern:

Be it known that l, SAMUEL R. Donns, a citizen of the United States, and a resident of llilkinsburg. in the county of Allegheny and State of ennsylvania, have invented a new and useful Improvement in Electromagnetic Switches, off which the following is a specification.

My invention relates to electromagnetic switches and particularly to such switches as are arranged to close only under predetermined conditions.

My invention has for its object to provide a switch of the above-indicated char acter which embodies a simple and efiicient means for preventing the operation of the switch when the current traversing its energizing winding exceeds a predetermined value.

According to the present invention, the

- movable element of the switchis controlled by an electromagnet comprising a coil in series with the translating device, the circuit of which is controlled by the switch. The circuit of the energizing coil is controlled by a second or auxiliary electromagnetic switch, the energizing coil of which is in series with the coil of the other or main electromagnet. hen the current traversing the circuit oi the coils exceeds a prede termined value, the auxiliary eletromagnetic switch closes a shunt circuit for the main coil, and the main switch cannot close until the current traversing the auxiliary coil falls to a predetermined value.

The details of my invention will be described in connection with the accompanying drawing, in which the single figure is a side view, partially in elevation and par tially in section, of a switch constructed in accordance with my invention.

A base member 1, which may be of slate or other suitable insulating material, supports an electromagnet comprising a core member 2 and a coil 3 that is in series with a motor or other translating device, the circuit of which is to be controlled. A closed conductor l, which may be, for example, a copper ring, is mounted upon the core memher 2 for a purpose to be later described. A movable contact member 5 is carried by an arm 6 that is pivotally supported by a memher 7. The movable contact member 5 coacts with a stationary contact member 8 that is secured to the base member 1;

Specification of Letters Patent.

, ELECTROMAGNETIC SWITCH.

Patented July 12, 1921 1916. Serial No. 98,805. i.

The terminals of the coil 3 are respectively connected to binding posts 9 and 10 which extend through the base member 1. A shunt circuit for the coil 3 is controlled by an electromagnetically operable switch comprising a stationary member ll that is supported by, and connected to, the binding post 9 and a pivotally mounted movable member 12 that is supported by, and electrically connected to, the binding post 10. The movable switch member 12 is controlled by an electromagnet' comprising a coil 13 and a movable core member 1.4. that is secured to themovable member 12. The valueof the current requiredto effect the engagement of the contact members 11. and y 12 may be varied by adjusting the position eta nut 15 on a screw-threaded shaft 16 that is connected to-themovable member 19.

It may be assumed that the movable contact memebr 5 and the arm 6 to which it is connected are in their respective open or inoperative positions. lVhen it is desired to close the switch, the circuit of the coil 3, may be closed in 'anysu'ltable manner. Cur-' rent then traverses a circuitcomprising conductor 17 which is connected to, and insulated from, the binding post 9, coil 13, contact memberll, binding post 9, coil 3, binding post 10 and conductor 18. If the current taversing the circuit above traced is below the value necessary to efiect the engagement of the contact members 11 and 12, the coil 3 is energized to effect the closing o'l the main switch at its contact members 5 and S. I y a If, however, the current exceeds a predetermined value, the coil 13 is energized to ellect the engagement of contact members 11 and 19 and thereby close a shunt circuit for the coil 3 by directly connecting the binding posts 10 and 11 which are connected I provide a s1mple means for preventing the energization of the coil of an electromagnet for controlling a switch or for deenergizing the coil should the current traversing it exceed a predetermined safe value. My invention is particularly adapted for use in connection with starting devices for electric motors in which it is desirable to prevent the shunting of the starting resistor as long as the current traversing the motor circuit exceeds a predetermined value. The switch may be employed, however, in connection with any apparatus in which the above-described method of control may be desirable.

I claim as my invention:

1. In a switch, the combination with a pair of coacting contact members and an electromagnet comprising a coil for effecting engagement of said contact members, of an electromagnetic switch for preventing the energization of said coil by short-circuiting the same when the current traversing it exceeds a predetermined value.

2. In a switch, the combination with a pair of c acting contact members and an electromagnet comprising a coil for effecting engagement of said contact members, of an electromagnetically operated switch for shunting said coil when the current traversing it exceeds a predetermined value.

In a switch, the combination with a pair of coacting contact members and an elcctromagnet comprising a coil for actuating one of the said Contact members, of means for deenergizing said coil when the current traversing it exceeds a predetermined value, said means comprising a switch member and an electromagnet having a coil in series with the first-mentioned coil.

4. In a switch, the combination with a pair of cooperating contact members and an electromagnet for effecting engagement of said contact members, of means for effecting the deenergization of said electromagnet after a predetermined current traverses the same, and means for opposing the effect of a sudden change in the value of the current supplied to said electromagnet.

In a switch, the combination with cooperating contact members and an electromagnet for effecting engagement of the contact members, of means for so deenergizing the said electromagnet' when the current traversing it exceeds a predetermined value that the contact members remain disengaged.

6. In a switch the combination with em operating contact members and an electromagnet tor actuating the contact men'ibers, of means for effecting the deenergization of the said electromagnet when the current traversing the same exceeds a predetermined value, and means for delaying the operation of the electromagnet when the current traversing the same changes suddenly.

7. In a switch, the combination with cooperating contact members and an electromagnet for actuating the contact n'lei'nbers. of means for effecting the deenergization ot the said electromagnet when the current traversing the same exceeds a predetermined value, and electromagnetic means for delaying the operation of the electromagnet under predetermined conditions.

In testimony whereof, I have hereunto subscribed my name this 29th day of April 1916.

SAMUEL B. DODDS. 

